As a result, prosecutors dropped a capital murder charge against Robinson and he was freed from jail.

Cox died from a gunshot wound to the head during a shootout at Robinson's home, 3229 87th St. Robinson, a 47-year-old unemployed automobile mechanic, barricaded himself inside the home after a dispute with his wife.

A tearful Robinson strode out of the Lubbock County Jail about 9:45 p.m. Friday flanked by his wife, Laura, and two of his three children, Zach and Shelby.

His first words were of the fallen Lubbock police officer.

''I prayed for that man and his family,'' Robinson said through tears.

He then expressed thanks for his freedom. ''Thank the good Lord,'' Robinson said looking skyward. ''It was not a good week.''

Before publicly announcing their findings at an 8:45 p.m. news conference, police administrators personally notified Cox's family and his fellow SWAT officers.

Detectives spent the week since the shooting collecting evidence, including 13 weapons, from Robinson's house.

''I'm sure you have a lot of questions about what happened, and I can tell you we don't know yet,'' Walker said. ''We'll find out. It's going to take some time.''

Robinson's attorney, Dan Hurley, said police and prosecutors acted on the new information appropriately.

''We're so pleased that the police didn't try to cover anything up and the district attorney's office did the right thing,'' Hurley said.

Investigators don't know the source of the fatal shot or if Robinson fired his weapons during the incident. At the request of police, FBI weapons experts will examine the scene Monday.

Hurley said Robinson contends he fired no shots during the standoff.

On Wednesday, Hurley suggested that ''friendly fire'' the accidental wounding of a comrade could have been responsible for Cox's death.

Police adamantly denied the claims based on information they believed true at the time, Walker said.

''The information and all the evidence we had at that point showed that it could not have been friendly fire,'' he said. ''Late Wednesday night things began to cause us to ask questions. At 7:30 this evening, we finally ruled on a piece of evidence that showed Richard Robinson did not fire the shot.''

As the investigation progressed, ''things didn't match up the way that we felt that they should,'' Assistant Police Chief Claude Jones said.

Television news footage of the shootout at first supported Robinson as the shooter, Jones said, but enhancements to the video raised concerns.

''We started seeing where we were able to exactly put Sgt. Cox when he was shot. We went out to the scene and were able to locate that spot within a few inches to a foot,'' he said. ''We saw problems with the bullet trajectory.''

''It may seem somewhat unusual, but I'm pleased that the system works and we are standing up here and releasing this man when the evidence now shows that he's not the person we had thought did the shooting,'' Sowder said.

Sowder said he would not speculate on whether Robinson might face other charges in connection with the standoff.

Robinson's house remains a crime scene, and police said they will continue to investigate the shooting. Under police policy, investigators seized all weapons fired by SWAT officers.

Cox was shot as the SWAT team attempted a ''break and rake'' maneuver in which windows are knocked out and curtains are cleared away. The technique is meant to intimidate the suspect as well as improve visibility into the house and make an entry point for tear gas.

Team members were not cleared to fire unless fired upon, police said. Gunfire erupted at 3:18 p.m., moments after the team leader ended a countdown synchronizing the movements of two squads approaching the house.

Perhaps more than a hundred rounds exploded during the next two to three minutes as SWAT officers scrambled for cover and then moved in to rescue Cox.

Robinson was injured during the exchange, and after police hurled massive amounts of tear gas into his house, he surrendered about 4:15 p.m.

Another officer, Jonny Hutson, was grazed by gunfire and suffered a minor injury.

Robinson was arraigned and booked into jail Wednesday after leaving the hospital.

Elizabeth Langton can be contacted at 766-8795 or blangton@lubbockonline.com